The LOM RDF binding- update 2003-06-19

Mikael Nilssonmini@nada.kth.se

The Knowledge Management Research GroupCentre for user oriented IT design

Royal Institute of Technology, Stockholm

http://kmr.nada.kth.se

Overview

● Use cases of LOM/RDF● XML binding compatibility issues● Status of the binding● Summary

Use cases 1: UR(Swedish educational broadcasting company)● Largest content producer in Sweden (state

owned)● ~3000 TV/Radio programs since 2001 (30,000

since 1970), plus books, web sites, etc.● +50 every week● Online archive of digital versions since February:● http://www.ur.se (in Swedish...)

UR: Web

UR: Metadata

● 4 application profiles (program, series, texts, websites)

● Several vocabularies:– DC (title, description, subject, relation, etc.)– DC Qualifiers (medium, MIME type, W3CDTF...)– LOM (difficulty, location, annotation, requirements..)– UR specific (accessibility, licenses, participants)– IMS content packaging

UR: Metadata refinements

● Refinements for e.g.:– identifiers (4-5 types in use in parallel at UR)– annotations (internal and external)– descriptions (different kinds for different purposes)– language (spoken/subtitles)

● Vocabularies for– audiences, types, media carriers, including

refinements of DC & LOM vocabulary.

UR features

● Easily modifiable metadata set, and easily configurable editor. Without disturbing, we can:– add fields– refine fields and values– add vocabularies

● Supports cross-search with DC/DCQ repositories. Demonstrated yesterday at UR:– UR, OAI, Swed. Agency of Education, digital

portfolios

Use case 2: Edutella

● P2P network for metadata exchange– http://edutella.jxta.org

● Supports any RDF metadata● Scenarios:

– Search for nuclear physics material (DC, DCQ)

– Search for learning material for primary school on nuclear physics (LOM)

– Search for courses including a certain piece of content (IMS CP)

– Search for annotations/opinions on this course.

Use case 3: RSS feeds● Rich Site Summary 1.0 based on RDF and DC

– http://purl.org/rss/1.0/

● Stephen Downes' RSS/LOM module:– http://www.downes.ca/xml/RSS_LOM.htm– “The RSS-LOM Module provides translation from IEEE-LOM to RSS 1.0

to allow learning object repositories to syndicate listings and descriptions of learning objects.”

– “An RSS feed provided by a learning object repository is harvested by a metadata repository and aggregated with feeds from other learning object repositories.”

– “These aggregated feeds are then made available as a searchable resource, the links provided ultimately pointing to the learning objects provided by the original learning object repositories.”

RSS/LOM example (extract)<dc:identifier>0-226-10389-7</dc:identifier><dc:title>Sample Learning Object</dc:title><dc:language>en</dc:language><dc:description>A sample learning object metadata file in RSS<dc:description><dc:subject>psychology</dc:subject><dc:coverage>1776-07-04</dc:coverage><lom-gen:structure>Atomic</lom-gen:structure><lom-gen:aggregationLevel>13</lom-aggregationLevel><lom-life:version>beta</lom-lifecycle:version><lom-life:status>final</lom-lifecycle:status><dc:publisher>National Research Council</dc:publisher><dc:editor>Rod Savoie</dc:editor><dc:creator>Stephen Downes</dc:creator><lom-meta:metadataScheme rdf:resource="&lom-meta;LOMv1.0"/><dc:format>text/html</dc:format><lom-tech:operatingSystem>Multi-OS<lom-tech:operatingSystem><lom-tech:browser>NetscapeCommunicator 4.7</lom-tech:browser><dcterms:extent>PT1H20M</dcterms:extent><lom-edu:interactivityType>Active</lom-edu:interactivityType><lom-edu:type>Exercise<lom-edu:type><lom-edu:interactivityLevel>Low</interactivityLevel><lom-edu:semanticDensity>High</lom-edu:semanticDensity><lom-edu:intendedEndUserRole>Manager</lom-edu:intendedEndUserRole><lom-edu:context>School</lom-edu:context><dcterms:audience>7-12</dcterms:audience><lom-edu:difficulty>Easy</lom-edu:difficulty><lom-edu:typicalLearningTime>PT1H20M</lom-edu:typicalLearningTime><lom-edu:description>This is intended to...</lom-edu:description><lom-edu:language>en</lom-edu:language><lom-rights:cost>SomeCost</lom-rights:cost><lom-rights:copyrightAndOtherRestrictions>SomeRestriction</lom-rights:copyrightAndOtherRestrictions><dc:rights>RightsBroker:RightsModel</dc:rights>

RDF <=> XML issues (for the BRG)

● Metadata term URIs

– LOM/XML has them, LOM/RDF has them– How to sync LOM/XML – LOM/RDF wrt CORES?

● Vocabulary term URIs

– Ability to give URI for a term. Needed in RDF– For LOM vocab: URIs for LOM vocabulary values– For local vocab: vocabulary XML format?

● LOM extensions are format specific

– Need to make this clear in the LOM/XML spec

RDF binding status

● Most details resolved in the direction of simplification

● Ballot-ready in principle– Binding is not perfect, but given the contraints we

have, it's as good as it gets● Goal: “Yes, you can use RDF and be LOM-

compatible. Here's how to do it:”● This goal is achievable with the current binding● See http://kmr.nada.kth.se/el/ims/md-lomrdf.html

Future

● Next-generation LOM visions:– allows for semantic extensions– plays nicer with other vocabularies– fits better into RDF world– in short: better knowledge representation capabilities

● The RDF binding work shows many of the problems and possibilities– will help inform LOM 2.0.

Issues for LOM 2.0

● The issue of semantic (not structural) extension:

– Subclasses, Subproperties, Element encodings● This needs a meta-model for metadata.

– DC has one: “element”, “element refinement”, “element encoding”).

– LOM has one: “element” “sub-element”, etc● RDF is a meta-model. DC is compatible, LOM is not. LOM's

metamodel is insufficient for dealing with semantic extension

● As LOM is structured, not flat: Needs conceptual modeling more than DC. What are objects, what are relations?